APPENDICES

Appendix I: Association between BMI and notified influenza infection (n=246494)

BMI category / Events
(n=1891) / Crude event rate/10000 person-years / Age and sex adjusted HR / *Adjusted HR
15.0-<18.5 / 32 / 15.2 (10.7-21.4) / 1.35 (0.94-1.94) / 1.31 (0.91-1.81)
18.5-<22.5 / 302 / 11.0 (9.9-12.4) / 1.11 (0.96-1.28) / 1.11 (0.95-1.28)
22.5-<25.0 / 383 / 9.6 (8.6-10.6) / Reference / Reference
25.0-<30.0 / 711 / 9.7 (9.0-10.4) / 1.07 (0.95-1.21) / 1.08 (0.95-1.22)
30.0-<40.0 / 416 / 11.0 (10.0-12.1) / 1.27 (1.10-1.45) / 1.27 (1.10-1.46)
40.0-<50.0 / 47 / 14.1 (10.6-18.8) / 1.70 (1.25-2.30) / 1.69 (1.24-2.29)

*Adjusted for: age, sex, income, area of residence,smoking

Appendix II: Primary hospitalisation ICD-10 codes* in participants with an influenza notification.

Diagnosis group / ICD10 codes / Number / % of total
Influenza, and pneumonia / J09-J18 / 362 / 38.1
Influenza due to identified zoonotic or pandemic influenza virus / J09 / 41
Influenza due to identified seasonal influenza virus / J10 / 180
Influenza, virus not identified / J11 / 15
Viral pneumonia, not elsewhere classified / J12 / 7
Pneumonia due to Streptococcus pneumoniae / J13 / 9
Pneumonia due to Haemophilus influenzae / J14 / 8
Bacterial pneumonia, not elsewhere classified / J15 / 10
Pneumonia due to other infectious organisms, not elsewhere classified / J16 / 1
Pneumonia, organism unspecified / J18 / 91
Other acute lower respiratory tract infection / J20-J22 / 56 / 5.9
Chronic lower respiratory tract infection / J40-J47 / 147 / 15.5
Acute upper respiratory tract infection / J00-J06 / 19 / 2.0
Other ICD 10 codes for respiratory diseases / 30 / 3.2
Ischaemic heart disease / I20-I25 / 11 / 1.2
Atrial fibrillation, cardiac arrhythmias, and congestive heart failure / I48-I50 / 32 / 3.4
Other ICD 10 I codes (cardiovascular system) / 19 / 2.0
Persons encountering health services for specific procedures and health care / Z47-Z51 / 96 / 10.1
All other ICD10 codes / 178 / 18.6
Total hospital separations / 950 / 100%

*see methods

Appendix III: Secondary respiratory hospitalisation ICD10 code* in participants with an influenza notification when the primary diagnosis code was not for a respiratory condition (ICD-10 J codes).

Primary diagnosis group / Secondary respiratory diagnosis group / N / %
Ischaemic heart disease (11 separations in 10 people) / Influenza and pneumonia / 5 / 45.5
Other J-codes only / 1 / 9.0
No J-codes / 5 / 45.5
Atrial fibrillation, cardiac arrhythmias, and congestive heart failure (32 separations in 29 people) / Influenza and pneumonia / 15 / 46.9
Other J-codes only / 6 / 18.7
No J-codes / 11 / 34.4
Other ICD10 I codes (19 separations in 19 people) / Influenza and pneumonia / 8 / 42.1
Other J-codes only / 3 / 15.8
No J-codes / 8 / 42.1
Health services visit for specific procedures and health care (Z47-Z51) (96 separations in 43 people) / Influenza and pneumonia / 19 / 19.8
Other J-codes only / 7 / 7.3
No J-codes / 70 / 72.9
Other ICD 10 codes (178 separations in 148 people) / Influenza and pneumonia / 51 / 28.7
Other J-codes only / 18 / 10.1
No J-codes / 109 / 61.2

*% are row percentages

Appendix IV: Association between BMI and influenza-related respiratory hospitalisation (n=246494)

BMI category / Events (n=623) / Crude event rate/10000 person-years / Age and sex adjusted HR / *Adjusted HR
15.0-<18.5 / 19 / 9.0 (5.7-14.1) / 2.52 (1.55-4.11) / 2.23 (1.37-3.64)
18.5-<22.5 / 87 / 3.2 (2.6-3.9) / 1.10 (0.83-1.45) / 1.07 (0.81-1.41)
22.5-<25.0 / 115 / 2.9 (2.4-3.4) / Reference / Reference
25.0-<30.0 / 230 / 3.1 (2.8-3.6) / 1.18 (0.94-1.47) / 1.19 (0.95-1.49)
30.0-<40.0 / 140 / 3.7 (3.1-4.4) / 1.59 (1.24-2.03) / 1.57 (1.22-2.01)
40.0-<50.0 / 32 / 9.6 (6.8-13.6) / 5.00 (3.36-7.43) / 4.81 (3.23-7.17)

*Adjusted for: age, sex, income, area of residence, smoking

Appendix V: Association between BMI and notified but not hospitalised influenza infection (n=246494)

BMI category / Events, (n=1268) / Crude event rate/10000 person-years / Age and sex adjusted HR / *Adjusted HR
15.0-<18.5 / 13 / 6.2 (3.6-10.6) / 0.81 (0.46-1.41) / 0.82 (0.47-1.43)
18.5-<22.5 / 215 / 7.9 (6.9-9.0) / 1.12 (0.93-1.34) / 1.12 (0.93-1.34)
22.5-<25.0 / 268 / 6.7 (5.9-7.5) / Reference / Reference
25.0-<30.0 / 481 / 6.6 (6.0-7.2) / 1.03 (0.89-1.20) / 1.03 (0.89-1.20)
30.0-<40.0 / 276 / 7.3 (6.5-8.2) / 1.14 (0.96-1.35) / 1.15 (0.97-1.37)
40.0-<50.0 / 15 / 4.5 (2.7-7.5) / 0.69 (0.41-1.16) / 0.70 (0.42-1.18)

*Adjusted for: age, sex, income, area of residence,smoking

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